Purchase of a 2OOkV electron microscope, digital data acquisition system, and distributed image analysis system for installation at the Department of Anatomy and Neurobiology is proposed. The electron microscope will be outfitted with a side entry goniometer with tilting angles as high as 60 degrees. It is intended for use in studying the three dimensional structure of neurons and glia in semithin sections from brain stained selectively using intracellular staining and immunocytochemical procedures. Quantitative studies of the sizes and shapes of cells and cell structures will be aided by construction of a digital image acquisition system based on archival storage of images on 5.25" optical disks. Analysis of images will be performed using a distributed image analysis system based on an inexpensive computer work station that will be installed in several laboratories within the department. These stations will communicate via an Ethernet network, as well as by their ability to read images from optical disk. They will employ a common program, Image, and standard networking software for use on all the workstations. The assembly of the digital image acquisition and analysis system, and the networking of stations will be undertaken in collaboration with the Department of Computer Science at the University of Tennessee, Memphis. The facility is designed to facilitate ongoing studies of the structure and function of neurons, glia, and their supporting tissues, conducted at the School of Medicine of the University of Tennessee.